Tonneau covers are among the popular and useful accessories for pickup trucks. They protect and conceal cargo, and increase fuel efficiency by reducing air resistance. Many of those covers are soft tarpaulins or hard material and simply lashed to hooks around the top of the walls of the cargo bed area, and this can make for difficult and sometimes-insecure installation.
Then, too, tool boxes and other accessories extend from side to side across the cargo bed area, say, directly behind the cab, and are permanently mounted to the top of the side walls with bolts. Among other drawbacks, such a tool box, since it extends above the walls of the cargo bed area, makes it difficult if not impossible to mount a tonneau cover.
It would be desirable to improve-upon such art.